Study of protective properties of universal corrosion inhibitor for oil and gas industry

Issue 24(1) 2019
Pages 29-48

G.R. Gurbanov, M.B. Adigezalova, S.M. Mammadli

Azerbaijan State Oil and Industry University

Keywords: imitation, hydrogen sulfide, carbon dioxide, polarization resistance, electrochemical impedance spectroscopy, ductility of steel, solid-phase diffusion, bactericide, inhibition, hydrogen

The inhibiting efficiency of the MARZA-1 inhibitor in relation to hydrosulphuric and carbon dioxide corrosion of St3 steel was studied in model reservoir water MI by the gravimetric method. Corrosion tests are carried out in tight vessels with a capacity of 0,5 l on samples of St3 steel in size of 30×20×1. MARZA-1 inhibitor allows to reach in the environment MI containing hydrogen sulfide the corrosion speed of the steel in the course of daily tests about 0,04 g/m2·h. only in concentration no less than 5 mg/l. However, with growth of duration of tests similar speed of corrosion is observed already at concentration of inhibitor of 3 mg/l. The same behavior is characteristic for the carbon dioxide environment and hydrosulphuric-carbon dioxide solutions. The bactericidal properties of the MARZA-1 inhibitor have been investigated related to two species of Desulfovibrio desulfuricans and Desulfomicrobium sulfate-reducing bacteria. The impact of the MARZA-1-inhibitor on the number of bacterial cells and formation of hydrogen sulfide in the Post-Gate-B nutrient medium has been evaluated. It was shown that, the MARZA-1 inhibitor reveals bacteriostatic action in relation to the sulfate-reducing bacteria. The study of the bactericidal properties of the inhibitor MARZA-1 showed that, it effectively suppresses the growth in the number of sulfate-reducing bacteria in the Post-gate nutrient medium, i.e. in the most comfortable conditions for their development and vital functions. So, after the introduction of the inhibitor and increasing its concentration in the Post-gate medium, the number of sulfate-reducing bacteria of both types is decreases. It was revealed that the degree of suppression in the number of Desulfovibrio desulfuricans microorganisms at MARZA-1 inhibitor concentration of 7.0 mg/l is higher than for Desulfomicrobium. In the latter case, 10.0 mg/l of MARZA-1 inhibitor is required to achieve this effect. The investigated MARZA-1 inhibitor inhibits the diffusion of hydrogen in the St3 in the in environment MI, saturated by H2S and CO2 separately and together, and also ensures the containment of plastic properties St3 after exploding in solvents, with comparisons with uninhibited samples. Based on the polarizationand impedance measurements, the first review of MARZA-1 is the influence on process of ionization of the metal. The interaction of parts ofl inhibitor in the adsorption film has been established. It was shown that the adsorption of the MARZA-1 inhibitor is a physical phenomenon. It has been established that the MARZA-1 inhibitor provides the most up-to-date screening layer for the formation of the St3, defining the effective metal protection.